Catheters and their use as medical devices are well known in the art. To minimize kinking and/or any infection to the patient, the catheter runs parallel under the skin for a short distance before it enters the vascular system or other desired system of the body. To place the catheter in this position, accomplish this result, the physician typically makes a first incision in the catheter entry point, i.e., the access point in the skin and in the vessel wall. A second incision is also made at the catheter exit point in the skin a short distance away from the first incision. The distal tip of the catheter is then attached to a tunneler. The tunneler is inserted into the second incision and pushed under the skin until it exits the first incision, thereby creating a “tunnel” between the two incisions. The tunneler is then used to pull the catheter through the “tunnel” underneath the skin. The catheter tip is then removed from the tunneler and the catheter is pushed back through the vascular access incision into the vessel incision, thereby allowing external access to the vascular system.
There are numerous types of tunnelers known in the art, including metallic tunnelers. See, for example, U.S. Pat. No. 6,565,594, the disclosure of which is incorporated herein by reference. Metallic tunnelers are typically designed to produce a reaction force—against the friction of pulling the catheter through the tunnel—by using a mechanical interference fit between the tunneler connection point and the internal geometry of the catheter tip. The requirements (i.e., geometry) of the interference fit are usually very stringent due to the required reaction force. Examples of the interference fit include non-compliant sharp barbs, ridges and threads. This stringent geometry can damage the catheter tip and could result in tip detachment, compounding an already serious procedure with patient safety and catheter functionality concerns.
To minimize the required reaction force and decrease such problems, a tunneler sheath is often used. The tunneler sheath typically contains a tapered tube that slides over the tunneler/catheter connection. Despite the use of tunneler sheath, damage to the catheter tip still remains a distinct possibility.
Current tunneler designs often contain a tapered metallic or plastic rod with a small diameter (e.g., 0.125 inches or less) that facilitates passage underneath the skin. This small diameter—when accompanied with blood or medical fluids—often makes it difficult for the physician to grip the tunneler, resulting in slippage and loss of control during the tunneler/catheter connection procedure.
The existing connections between catheter tips and tunnelers typically contain only a single connection feature that is used in the lumen of the tip of a single or multiple lumen catheter. For multiple lumen catheters, the tunnelers typically have connection features with lengths that are substantially the same for each lumen. When such tunnelers are used with multi-lumen catheters having staggered tip geometry, it can be difficult to separate the connection features to allow one connection feature to enter the more distal lumen and the other to enter the more proximal lumen.